Ink jet apparatus

ABSTRACT

An ink jet apparatus includes an ink jet head, capping element and sucking element. The ink jet head includes a plurality of ink discharge openings each adapted to discharge ink therefrom and a common ink chamber communicated with the ink discharge openings for seeding ink to the ink discharge openings via an ink feeding port. The capping element serves as an element for covering the ink discharge openings of the ink jet head therewith and includes an ink suction port. In addition, the sucking element serves as an element for sucking ink from the ink discharge openings of the ink jet head via the ink suction port. The ink suction port is located at a position apart from a position opposing the ink feeding port of the ink jet head.

This application is a continuation of application Ser. No. 08/365,736filed Dec. 29, 1994, now abandoned.

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to an ink jet apparatus. In thisspecification, it should be construed that a word "recording" involves atechnical concept of applying ink to a various kind of ink receivingmedium such as cloth, thread, paper, sheet-like material and so fortheach adapted to receive ink thereon to be printed, and that words "arecording apparatus" involve a technical concept defined by variouskinds of information processing systems or a printer serving as anoutputting system for each of the information processing system. Thepresent invention can be applied to each of the information processingsystem and the printer as mentioned above

2. DESCRIPTION OF THE RELATED ART

A recording apparatus such as a printer, a copying machine, a facsimileor the like, or a recording apparatus usable as an outputting system fora composite type electronic system or a work station inclusive of acomputer, a word processor or the like is constructed such that an imageis recorded on a recording material (recording medium) such as a paper,a plastic sheet or the like based on given image information. An ink jetrecording process for enabling each recording operation to be achievedwith a high quality of recorded image at a high speed is employed in arecording apparatus of the foregoing type.

Generally, an ink jet apparatus includes an ink jet head which issubstantially composed of a plurality of ink discharge openings arrangedin the row-shaped pattern on a discharge opening surface, a common inkchamber communicated with the ink feeding ports for feeding ink to theink discharge openings, and a tank portion having an ink feeding portformed thereon for feeding ink to the common ink chamber through the inkfeeding port.

With respect to the ink jet apparatus including the ink jet headconstructed in that way, there sometimes arises a malfunction that theviscosity of ink is increased due to evaporation of volatile componentsin ink through the ink discharge openings induced by the dry atmosphereor a similar factor while any recording operation is not performed withthe ink jet apparatus with the result that merely incorrect inkdischarge is achieved or any ink discharge can not be achieved with theink jet apparatus. In this case, since it becomes difficult that ink isdischarged from respective discharge openings, there arises anothermalfunction that a quality of recorded image is degraded.

To cope with the aforementioned malfunctions, discharge recoveringtreatment has been hitherto periodically conducted for the ink jet headirrespective of whether or not a recording operation is performed withthe ink jet apparatus. In practice, an discharge recovering treatmentunit substantially composed of a cap member for forming a closed spaceinclusive of a discharge opening plane while coming in tight contactwith the discharge opening plane defined by a plurality of ink dischargeopenings of the ink jet head, a suction pump fitted to the cap memberfor bringing the closed space in the negative pressure state, and inkdischarge openings for discharging ink discharged in the closed space bythe suction force generated by the suction pump is used in order toconduct the foregoing type of discharge recovering treatment.

To facilitate understanding of the present invention, a typicalconventional ink jet apparatus will be described below mainly in respectof a structure and a mode of operation of each of an ink jet head and andischarge recovering treatment unit with reference to FIG. 12 and FIG.13.

FIG. 12 is a fragmentary sectional view of the conventional ink jetapparatus, showing the opened state that a capping unit is parted awayfrom an ink jet head, and FIG. 13 is a fragmentary sectional view of theconventional ink jet apparatus similar to FIG. 12, showing the closedstate that the capping unit is brought in tight contact with the ink jethead. Referring to FIG. 12, an ink jet head 1 is held in such a manneras to move in the direction perpendicular to the plane of the drawingwith the aid of a moving mechanism and a holding mechanism each of whichis not shown in the drawing. The ink jet head 1 includes a tank portion1a in which ink Ik is fed by actuating a certain mechanism (not shown)so as to allow a certain amount of ink Ik to be storably receivedtherein.

An ink feeding port 1b is arranged at the central part on the lower wallof the tank portion 1a so that the tank portion 1a is communicated witha common ink chamber 1c to be described later via the ink feeding port1b. The common ink chamber 1c is located below the tank portion 1a. Thecommon ink chamber 1c serve as an ink tank storing portion for feedingink Tk in the tank portion 1a to all of ink discharge openings. In FIG.12, reference numeral 1d designates a discharge opening plane which isdefined by all the ink discharge openings, and reference numeral 1edesignates a discharge opening group which is located in the vicinity ofthe ink feeding port 1b. The discharge opening group 1c is located atthe central part as viewed from the standpoint of the whole inkdischarge openings. In addition, reference numerals 1f and 1g designatedischarge opening groups each of which is parted away from the inkfeeding port 1b. Each of the discharge opening groups 1f and 1g islocated at the end edge part as viewed from the standpoint of the wholeink discharge openings.

A peripheral wall portion 2b is formed along the peripheral edge portionof an upper surface 2a of a cap 2 serving as capping means in order toassure that a discharge opening plane 1d of the ink jet head 1 isthrusted by the peripheral wall portion 2b of the cap 2 along the wholeperipheral edge thereof after the cap 2 is raised up by actuating amovable mechanism to be described later so as to come in tight contactwith the discharge opening plane 1d of the ink jet head 1. Theperipheral wall portion 2b of the cap 2 adapted to come in contact withthe ink jet head 1 is molded of an elastic material such as a rubber ora similar material in consideration of conditions such as absorption ofshock arising at the time of coming in contact with the ink jet head 1,improvement of the contact state after the foregoing time and so forth.

An ink suction port 2c is formed at the central part of the uppersurface 2a of the cap 2, and an ink suction pipe 2d suspends from theink suction port 2c. The lower end of the ink suction pipe 2d isconnected to a suction pump 4 via a pipe 3 extending therebetween.

The cap 2 is held by a holder 5 capable of being displaced in theupward/downward direction with the aid of the movable mechanism (notshown). With this construction, it is possible to bring the cap 2 intight contact with the discharge opening plane 1d of the ink jet head 1or release the cap 2 from the tight contact state by actuating themovable mechanism.

In addition, an ink absorbing member 6 for absorbing ink Ik therein isplaced on the upper surface 2a of the cap 2.

Next, a mode of suction recovering operation of the conventional ink jetapparatus constructed in that way will be described below.

First, as shown in FIG. 12, the ink jet head 1 is displaced to a homeposition by actuating a driving mechanism (not shown) so that thedischarge opening plane 1d of the ink jet head 1 faces to the uppersurface 2a of the cap 2 in the spaced relationship. Subsequently, theholder 5 is displaced in the upward direction by actuating the movablemechanism (not shown) so that the peripheral wall portion 2b of the cap2 held on the holder 5 is brought in tight contact with the dischargeopening plane 1d of the ink jet head 1 along the peripheral edge of thelatter with a certain intensity of thrusting force, whereby the space infront of the discharge opening plane 1d of the ink jet head 1 becomes aclosed space. When the suction pump 4 is driven, the pressure in theclosed space becomes negative pressure. Thus, ink Ik in the tank portion1a is sucked through the respective ink suction ports, causing inkhaving an increased viscosity and gas bubbles remaining in therespective ink suction ports and the common ink chamber 1c to beremovably dislocated into the interior of the closed space. At the sametime, ink Ik kept in the normal state is filled in the respective inkdischarge openings from the common ink chamber 1c. As ink Ik isintroduced into the closed space, it is absorbed in the ink absorbingmember 6. Thereafter, ink Ik is displaced in the downward directionthrough the ink absorbing member 6, and finally, it is collected in atank (not shown) via the ink suction pipe 2d and the pipe 3.

Next, after the closed space is released from the negative pressurestate by actuating a negative pressure releasing mechanism such as astop valve or the like (not shown) fitted to the cap 2, the driving ofthe suction pump 4 is interrupted, causing the holder 5 to be lowereduntil the cap 2 is parted away from the discharge opening plane 1d ofthe ink jet head 1, whereby a series of suction recovering operationsare completed. It should be noted that the ink absorbing member is notshown in FIG. 13 for the purpose of simplification of illustration.

However, the conventional ink jet apparatus constructed in theabove-described manner has the following drawback. Specifically, sincethe ink feeding port 1b of the ink jet head 1 and the ink suction port2c of the cap 2 face to each other in the upward/downward direction, amanner of allowing Ink to flow through respective discharge openings atthe central part of a row of ink discharge openings is different fromthat of allowing ink to flow through respective discharge openings atthe peripheral part of a row of ink discharge openings. For this reason,an excellent quality of recorded image can not be maintained because thesuction recovering state differs depending on the position occupied byeach discharge opening group.

In more detail, as shown in FIG. 13, since ink remaining in the vicinityof the central discharge opening group 1e among a group of ink dischargeopenings is located around the line extending between the ink feedingport 1b and the ink suction port 2c, it is largely affected by a highintensity of sucking force. At this time, since the pressure lossinduced by the ink absorbing member 6 interposed between the ink jethead 1 and the cap 2 is small, ink smoothly flows in the closed space ata high speed in the P arrow-marked direction as seen in the drawing,resulting in ink having an increased density and gas bubbles remainingin the discharge opening group 1e being removably dislocated from thelatter at a high efficiency. On the contrary, since ink remaining in thevicinity of each of discharge opening groups if and 1g located along theend edge of a group of ink discharge openings is parted away from theline extending between the ink feeding port 1b and the ink suction port2c, it is not largely affected by the suction force, and moreover, thepressure loss is relatively increased due to the presence of the inkabsorbing member 6, ink slowly flows at a low speed in the Rarrow-marked direction, resulting in ink having an increased viscosityand gas bubbles remaining in respective discharge openings in thedischarge opening groups 1f and 1g failing to be removably dislocated toa sufficient extent.

As is apparent from the above description, as far as the conventionalink jet apparatus constructed in that way is concerned, uniformdischarging properties can not be recovered with the whole dischargeopening groups no matter how discharge recovering treatment is conductedfor a group of ink discharge openings. This leads to the result that adensity of recorded image fluctuates over the whole area of the latter,an moreover, and ink discharge is incorrectly achieved with theconventional ink jet apparatus, resulting in each recording operationbeing achieved at a high level of quality only with much difficulties.Especially, when the number of discharge openings is increased, theaforementioned malfunctions can remarkably be recognized.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of theaforementioned background.

An object of the present invention is to provide an ink jet apparatuswhich is constructed such that uniform discharging properties can berecovered for all discharge openings after completion of dischargerecovering treatment.

According to a first aspect of the present invention, there is providedan ink jet apparatus which comprises capping means for capping aplurality of ink discharge openings of an ink jet head therewith, theink jet head including the plurality of ink discharge openings todownwardly discharge inks a common ink chamber communicated with theplurality of ink discharge openings, and an ink feeding port for feedingink to the common ink chamber; and sucking means for sucking ink fromthe plurality of ink discharge openings of the ink jet head via an inksuction port while the ink jet head is capped by the capping means, theink suction port being arranged at a position apart from a positionopposing to the ink feeding port.

It may further comprise an ink flow restricting means for reducing amagnitude of resistance against the flowing of ink corresponding to thedistance from the ink suction port, the ink flow restricting means beingarranged in the capping means.

It may further comprise an ink absorbing member for absorbing ink, theink absorbing member being arranged in the capping means.

Here, a degree of coarseness of the ink absorbing member may beincreased in proportion to the distance from the ink suction port.

The ink jet head may include an energy generating element for generatingenergy to be utilized for discharging ink from the plurality of inkdischarge openings.

Here, the energy generating element may be an electro-thermal convertingelement for generating thermal energy for allowing a phenomenon of filmboiling to appear in ink.

The plurality of ink discharge openings may be arranged in therow-shaped pattern across the whole width of an ink receiving medium towhich is ink discharged from the plurality of ink discharge openings.

According to a second aspect of the present invention, there is providedan ink jet apparatus which comprises capping means for capping aplurality of ink discharge openings of an ink jet head therewith, theink jet head including the plurality of ink discharge openings todownwardly discharge ink, a common ink chamber communicated with theplurality of ink discharge openings for feeding ink to the common inkchamber; and sucking means for sucking ink from the plurality of inkdischarge openings of the ink jet head via an ink suction port while theink jet head is capped by the capping means, wherein the ink suctionport being arranged at a position where an image line connecting the inksuction port with the ink feeding port is crossed with almost all ofextending lines along the discharge direction of ink discharged from theink discharge openings, respectively.

Here, it may further comprise an ink flow restricting means for reducinga magnitude of resistance against the flowing of ink corresponding tothe distance from the ink suction port, the ink flow restricting meansbeing arranged in the capping means.

It may further comprise an ink absorbing member for absorbing ink, theink absorbing member being arranged in the capping means.

Here, a degree of coarseness of the ink absorbing member may beincreased in proportion to the distance from the ink suction port.

The ink jet head may include an energy generating element for generatingenergy to be utilized for discharging ink from the plurality of inkdischarge openings.

Here, the energy generating element may be an electro-thermal convertingelement for generating thermal energy for allowing a phenomenon of filmboiling to appear in ink.

The plurality of ink discharge openings may be arranged in therow-shaped pattern across the whole width of an ink receiving medium towhich ink is discharged from the plurality of ink discharge openings.

According to a third aspect of the present invention, there is providedan ink jet apparatus which comprises capping means for capping aplurality of ink discharge openings of an ink jet head therewith, theink jet head including the plurality of ink discharge openings todownwardly discharge ink, a common ink chamber communicated with theplurality of ink discharge openings, the chamber including an inkfeeding port for feeding ink to the common ink chamber; sucking meansfor sucking ink from the plurality of ink discharge openings of the inkjet head via an ink suction port while the ink jet head is capped by thecapping means, the ink suction port being arranged at a position apartfrom a position opposing to the ink feeding port; and a flow restrictingmeans arranged in the capping means for reducing a magnitude ofresistance against the flowing of ink corresponding to the distance fromthe ink suction port.

Here, the ink jet head may include an energy generating element forgenerating energy to be utilized for discharging ink from the pluralityof ink discharge openings.

The energy generating element may be an electro-thermal convertingelement for generating thermal energy for allowing a phenomenon of filmboiling to appear in ink.

The plurality of ink discharge openings may be arranged in therow-shaped pattern across the whole width of an ink receiving medium towhich ink is discharged from the plurality of ink discharge openings.

According to a fourth aspect of the present invention, there is providedan ink jet apparatus which comprises capping means for capping aplurality of ink discharge openings of an ink jet head therewith, theink jet head including the plurality of ink discharge openings todownwardly discharge ink, a common ink chamber communicated with theplurality of ink discharge openings, the an ink feeding port for feedingink to the common ink chamber; sucking means for sucking ink from theplurality of ink discharge openings of the ink jet head via an inksuction port while the ink jet head is capped by the capping means, theink suction port being arranged at a position apart from a positionopposing to the ink feeding port; and an ink absorbing member forabsorbing ink, whose a degree of coarseness being increased inproportion to the distance from the ink suction port.

Here, the ink jet head may include an energy generating element forgenerating energy to be utilized for discharging ink from the pluralityof ink discharge openings.

The energy generating element may be an electro-thermal convertingelement for generating thermal energy for allowing a phenomenon of filmboiling to appear in ink.

The plurality of ink discharge openings may be arranged in therow-shaped pattern across the whole width of an ink receiving medium towhich ink is discharged from the plurality of ink discharge openings.

According to the present invention, since the ink suction port is notaligned with the ink feeding port but the former is positionallydeviated from the latter, sucking force can uniformly be applied to allthe ink discharge openings. This makes it possible to uniformalize theflowing of ink passing through respective discharge openings. Thus,since a sufficiently acceptable recovering state can be obtained overthe whole range as seen in the direction of a row of discharge openings,an excellent quality of recorded image can be maintained with the inkjet apparatus.

The above and other objects, effects, features and advantages of thepresent invention will become apparent from reading of the followingdescription on preferred embodiments thereof taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements in a first embodiment of an ink jetapparatus according to the present invention;

FIG. 2 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a second embodiment of an ink jetapparatus according to the present invention;

FIG. 3 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a third embodiment of an ink jetapparatus according to the present invention;

FIG. 4 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a fourth embodiment of an ink jetapparatus according to the present invention;

FIG. 5 is a plan view showing the capping means as viewed in the Aarrow-marked direction in FIG. 4, showing the state that a series of inkdischarge openings formed on the ink jet head are arranged in theoverlapped state;

FIG. 6 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a fifth embodiment of an ink jetapparatus according to the present invention;

FIG. 7 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a sixth embodiment of an ink jetapparatus according to the present invention;

FIG. 8 is a plan view of the capping means as viewed in the Barrow-marked direction in FIG. 7, showing the state that a series of inkdischarge openings formed on the ink jet head are arranged in theoverlapped state;

FIG. 9 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of a seventh embodiment of an inkjet apparatus according to the present invention;

FIG. 10 is a plan view of the capping means as viewed in the Carrow-marked direction in FIG. 9;

FIG. 11 is a fragmentary sectional view showing an ink jet head andcapping means as essential elements of an eighth embodiment of an inkjet apparatus according to the present invention;

FIG. 12 is a fragmentary sectional view of a conventional ink jetapparatus, showing the opened state that capping means is parted awayfrom an ink jet head so as to allow it to exhibit an opened contour;

FIG. 13 is a fragmentary sectional view of the conventional link jetapparatus similar to FIG. 12, showing the closed state that the cappingmeans is brought in tight contact with the ink jet head to form a closedspace therebetween; and

FIG. 14 is a partially exploded perspective view showing the wholestructure of a further embodiment of an ink jet apparatus according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail hereinafter withreference to the accompanying drawings which illustrate preferredembodiments hereof.

[Embodiment 1]

FIG. 1 is a sectional view of an ink jet apparatus constructed inaccordance with a first embodiment of the present invention, showing thestructure of an ink jet head and capping means constituting the ink jetapparatus as essential components. It should be noted that samecomponents as those constituting an ink jet head and capping means in aconventional ink jet head shown in FIG. 12 and FIG. 13 are representedby same reference numerals and repeated description on these componentsis herein omitted for the purpose of simplification.

A characterizing feature of this embodiment consists in that two inksuction ports 12c and 12d are arranged at the positions substantiallyfacing to a discharge opening group 1f and a discharge opening group 1gon the opposite end sides of a group of discharge ports of which centralpart faces to an ink feeding port 1b, and each of the ink dischargeopenings serves as to discharge ink in the downward direction. Referringto FIG. 1, at least a peripheral wall portion 12a of a cap 12 is moldedof an elastic material, and a first ink suction port 12c and a secondink suction port 12d are formed on a substantially horizontallyextending upper surface 12b of the cap 12. The first and second inksuction ports 12c and 12d are prepared in the form of opening portionsat the upper ends of a first ink suction pipe 12e and a second inksuction pipe 12f both of which are communicated with a suction pump tobe described later via a first pipe 13a and a second pipe 13b. As isapparent from the drawing, both the pipes 13a and 13b merge with acollective pipe 13c which extends to the suction pump. A holder 14serves to hold the cap 12 thereon, and it can be displaced in theupward/downward direction by actuating a movable mechanism (not shown).

Next, description will be made below with respect to a mode of operationto be performed by the ink jet head 1 and the cap 12 constructed in thatway during suction recovering treatment as well as suction recoveringproperties of the ink jet head 1 and the cap 12.

When the suction pump (not shown) is driven while the cap 12 shown inFIG. 1 is brought in tight contact with a discharge opening plane 1d ofthe ink jet head 1 with an adequate intensity of thrusting force,negative pressure arises in the closed space between the dischargeopening plane 1d of the ink jet head 1 and the cap 12, causing ink Ik tobe sucked into the closed space through respective discharge openingsarranged in the row-shaped pattern. At this time, the distance asmeasured from the ink feeding port 1b to a central discharge openinggroup 1e is kept unchanged in contrast with the conventional ink jetapparatus but the distance from the ink feeding port 1b to the first andsecond ink suction ports 12c and 12d is elongated. Although the distancefrom the ink feeding port 1b to the discharge opening groups 1f and 1ginclusive of the peripheral parts of the latter is kept unchanged, sincethe ink suction ports 12c and 12d are arranged in the vicinity of to thedischarge opening groups 1f and 1g, the difference in ink flow betweenthe central discharge opening group 1e inclusive of the peripheral partof the latter and the discharge opening groups 1f and 1g inclusive ofthe peripheral parts of the latter is reduced, resulting in ink havingan increased viscosity and gas bubbles being uniformly dischargedthrough all the discharge openings. Consequently, a sufficientlyacceptable discharge recovering state can be obtained, and moreover, anexcellent quality of recorded image can be maintained with the ink jetapparatus.

Thereafter, the ink jet head and the cap constructed in theabove-described manner are incorporated in, e.g., an ink jet apparatusshown in FIG. 14 for the purpose of discharging ink from the ink jethead.

The ink jet apparatus shown in FIG. 14 is a full-colored serial typeprinter which includes four exchangeable ink jet heads corresponding tofour kinds of colored inks, i.e., black (Bk), cyan (C), magenta (M) andyellow (Y). Each of the ink jet heads used for the foregoing printer hasa resolution of 400 dpi and a driving frequency of 4 kHz and includesone hundred twenty eight ink discharge openings.

In FIG. 14, reference character C designates four ink jet headcartridges which are arranged corresponding to four kinds of colorsrepresented by Y, M, C and Bk. Each ink jet head cartridge C isconstructed such that an ink jet head and an ink tank having ink to befed to the ink jet head storably received therein are made integral witheach other. Each ink jet head cartridge C is detachably mounted on acarriage 2. The carriage 2 is engaged with a guide shaft 11 in such amanner as to slidably move along the guide shaft 11, and moreover, it isfastened to part of a driving belt 52 adapted to be displaced by a mainscanning motor (not shown). With this construction, the ink jet headcartridge C can be displaced to perform scanning along the guide shaft11. Reference numerals 15 and 16 designate conveying rollers arranged onthe far side in the recording range defined by the scanning performed bythe ink jet head cartridge C, and reference numeral 17 and 18 likewisedesignate conveying rollers arranged on the near side in the recordingrange as viewed in the drawing. The conveying rollers 15 to 18 extendsubstantially in parallel with the guide shaft 11. The conveying rollers15 to 18 are rotationally driver by an auxiliary scanning motor (notshown) to stepwise convey a recording medium P in the auxiliary scanningdirection. As the recording medium F is conveyed, a recording surface isformed on the recording medium P while facing to the ink dischargeopening plane defined by the ink jet head cartridges C.

A plurality of units associated with the aforementioned suctionrecovering treatment are arranged while they are exposed to the movablerange of the ink jet head cartridges C located adjacent to the recordingrange of the same. In FIG. 14, reference numeral 300 designates fourcapping units which are arranged in the suction recovering systemcorresponding to the four ink jet head cartridges C each including anink jet head. As the carriage 2 is displaced by a displacing mechanism(not shown), the capping units 300 can slidably be displaced in theleftward/rightward direction, and moreover, they can be displaced in theupward/downward direction. While the carriage 2 stays at a homeposition, it is operatively connected to ink jet head portions of theink jet head cartridges C so as to allow them to be capped with thecapping units 300.

Reference numeral 500 designates a pump unit which serves to such inkfrom ink discharge openings of the ink jet heads inclusive of theperipheral part of the latter via the capping units 300.

[Embodiment 2]

FIG. 2 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with a second embodiment of the presentinvention, showing the structure of an ink jet head and capping meansconstituting the ink jet apparatus as essential components.

A characterizing feature of this embodiment consists in that an ink jethead including two ink feeding ports at the predetermined positions iscombined with the conventional cap 2 shown in FIG. 12 and FIG. 13.Specifically, in this embodiment, the ink jet head 20 includes a tankportion 1a having the substantially same structure as that in Embodiment1, and a first ink feeding part 20a and a second ink feeding port 20bare formed through the lower wall of the tank portion 1a at thepositions facing to a discharge opening group 1f and a discharge openinggroup 1g formed in the vicinity of the opposite end edges of a group ofink discharge openings with a common ink chamber 1c interposedtherebetween.

On the assumption that discharge recovering treatment is conducted withthe ink jet head 20 constructed in that way, description will be madebelow with respect to how ink flows through the respective dischargeopening groups.

As is apparent from the drawing, each of the discharge opening group 1fand the discharge opening group 1g inclusive of the peripheral parts ofthe latter has a short distance measured from each of the ink feedingports 20a and 20b but it has a long distance measured from an inksuction port 2c. On the contrary, a central discharge opening group 1einclusive of the peripheral part of the latter has a long distancemeasured from the ink feeding port 20a and the ink feeding port 20b butit has a short distance measured from the ink suction port 2c. With suchconstruction, the flowing state of ink not only through the dischargeopening group 1f and the discharge opening group 1g inclusive of theperipheral parts of the latter but also through the central dischargeopening group 1e inclusive of the peripheral part of the latter can beuniformalized.

Also in this embodiment, since ink having an increased viscosity and gasbubbles remaining in each discharge opening can reliably and uniformlybe discharged from the whole group of ink discharge ports of the ink jethead 20, a sufficiently acceptable discharge recovering state can beobtained, and moreover, an excellent quality of recorded image can bemaintained with the ink jet apparatus.

The ink jet head 20 and the cap 2 constructed in the above-describedmanner can practically be used like in Embodiment 1 by incorporatingthem in, e.g., the ink jet apparatus shown in FIG. 14.

[Embodiment 3]

FIG. 3 is a sectional view of an ink jet apparatus constructed inaccordance with a third embodiment of the present invention, showing thestructure of an ink jet head and capping means constituting the ink jetapparatus as essential components.

A characterizing feature of this embodiment consists in that theposition occupied by an ink feeding port of the ink jet head is largelyparted away from the position occupied by an ink suction port of thecapping means. Specifically, in this embodiment, the ink jet head 21includes a tank portion 1a, and an ink feeding port 21a is formedthrough the lower wall of the tank portion 1a at the position facing toa discharge opening group 1g on the right-hand end side of a group ofink discharge ports. On the other hand, a cap 22 is molded of an elasticmaterial, and an ink suction port 22c is formed on an upper surface 22bof the cap 22 at the position facing to a discharge opening groove 1f onthe left-hand end side of the group of ink suction ports. The inksuction port 22c serves as an upper end opening portion of an inksuction pipe 22d which suspends from the cap 22, and the ink suctionpipe 22d is connected to a suction pump (not shown) via a pipe 3.

Next, description will be made below with respect to the flowing of inkin the case that suction recovering treatment is conducted for the inkjet head constructed in that way using the cap 22.

The discharge opening group 1g inclusive of the peripheral part of thelatter located on the right-hand side as seen in the drawing is spacedaway from the ink feeding port 21a by a short distance, while it islocated remote from the ink suction port 22c. In addition, the dischargeopening group 1f inclusive of the peripheral part of the latter locatedon the left-hand side is spaced away from the ink feeding port 21a by along distance, while it is spaced away from the ink suction port 22c bya short distance. A central discharge opening group 1e is arranged inthe intermediate positional relationship between both the dischargeopening groups 1f and 1g. With this construction, the flowing of ink inthe vicinity of the discharge opening group 1g located on the right-handend side, the central discharge opening group 1e located in theintermediate side and the discharge opening group 1f located on theleft-hand end side can be uniformalized.

Therefore, also in this embodiment, since ink having an increasedviscosity and gas bubbles can reliably and uniformly be discharged fromthe whole group of ink discharge ports of the ink jet head 21, asufficiently acceptable discharge recovering state can be obtained, andmoreover, an excellent quality of recorded image can be maintained withthe ink jet apparatus.

In each of Embodiments 1 to 3, in the case that the number of dischargeopenings of the ink jet head is additionally increased, causing thenumber of ink feeding ports to be correspondingly increased to three orfour, the flowing of ink can be uniformalized over the whole group ofdischarge openings by forming a plurality of ink suction ports not onlyat the substantially intermediate position as seen in the direction ofarrangement of the respective ink feeding ports of the dischargeopenings in the cap but also at the opposite ends of the cap.

The ink jet head 21 and the cap 22 constructed in that way canpractically be used like in Embodiment 1 by incorporating them in, e.g.,the ink jet apparatus shown in FIG. 14.

[Embodiment 4]

FIG. 4 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with a fourth embodiment of the presentinvention, showing the structure of an ink jet head and capping meansconstituting the ink jet apparatus as essential components, and FIG. 5is a plan view of the capping means as viewed in the A arrow-markeddirection in FIG. 4, showing the state that a series of ink dischargeopenings formed on the ink jet head in the overlapped state.

A characterizing feature of this embodiment consists in that the ink jetapparatus has the substantially same structure as that in Embodiment 1shown in FIG. 1 and a flow restricting member 25 is arranged on an uppersurface 12b of a cap 12 for restricting the flowing of ink sucked fromrespective discharge openings.

The flow restricting member 25 exhibits a substantially rhombic contourand includes a central portion 25a having a large width and first andsecond end portions 25b and 25c symmetrically located with the centralportion 25a as a center and each having a small width as viewed in thetransverse direction. The intermediate part between the central portion25a and each of the opposite end portions 25b and 25c is contoured suchthat a width of the flow restricting member 25 is gradually reduced fromthe central portion 25a.

As shown in FIG. 4, the flow restricting member 25 is placed on aplurality of protuberances 12f formed on the upper surface 12b of thecap 12, whereby a space capable of being used as an ink flow passage canbe formed between the cap 12 and the flow restricting member 25.

Next, description will be made below with respect to the flowing stateof ink in the case that discharge recovering treatment is conducted forthe ink jet head 1 by using the cap 12 including the flow restrictingmember 25 constructed in that way.

The flowing state of ink is positively uniformalized depending on thepositional relationship established among the respective dischargeopenings, an ink feeding port 1b, and ink suction ports 12c and 12d inthe same manner as described in Embodiment 1. In this embodiment, sincethe flow restricting member 25 is additionally arranged on the cap 12,the flowing state of ink can more positively be uniformalized owing tothe arrangement of the flow restricting member 25. Specifically, asshown in FIG. 5, the flow restricting member 25 is contoured in such amanner that a gap between the flow restricting member 25 and aperipheral wall portion 12a, i.e., an inner wall surface of the cap 12is largely reduced at the central portion 25a facing to an ink feedingport 1b and the foregoing gap is gradually enlarged toward the oppositeend portions 25b and 25c facing to the ink suction ports 12c and 12d.With such construction, a large magnitude of resistance against theflowing of ink arises around a central discharge opening group 1e,causing the flowing of ink to be suppressed, and a small magnitude ofresistance against the flowing of ink arises around discharge openinggroups 1g and 1f on the opposite end sides of the cap 12 without anyhindrance against the flowing of ink, whereby the flowing state of inkcan additionally be uniformalized by the flow restricting member 25.This embodiment is advantageously applicable especially when the ink jethead 1 is designed in the form of a multi-discharge opening.

The ink jet head 1 and the cap 12 constructed in that way canpractically be used like in Embodiment 1 by incorporating them in, e.g.,the ink jet apparatus shown in FIG. 14.

[Embodiment 5]

FIG. 6 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with a fifth embodiment of the presentinvention, showing the structure of an ink jet head and capping meansconstituting the ink jet apparatus as essential components.

A characterizing feature of this embodiment consists in that the ink jetapparatus has the substantially same structure as that in Embodiment 3shown in FIG. 3 and an ink absorbing member 26 having a specialstructure is placed on a group of protuberances 22e formed on an uppersurface 22b of a cap 22.

As shown in FIG. 6, the ink absorbing member 26 is composed of a firstink absorbing portion 26a, a second ink absorbing portion 26b and athird ink absorbing portion 26c each having a different density, andthese ink absorbing portions 26a, 26b and 26c are integrated with eachother to constitute a single ink absorbing member. In this embodiment,the first ink absorbing portion 26a facing to an ink feeding port 21bhas a highest density, and a density of each of the remaining inkabsorbing portions is stepwise reduced in accordance with the order ofthe second ink absorbing portion 26b and the third ink absorbing portion26c.

Next, description will be made below with respect to the flowing of inkin the case that discharge recovering treatment is conducted for the inkjet head 21 by using the cap 22 including the ink absorbing member 26constructed in the above-described manner.

A large magnitude of resistance against the flowing of ink arises arounda discharge opening group. 1g located on the right-hand end side of theink jet head 21 due to the presence of the first ink absorbing portion26a having a highest density, i.e., a dense structure, causing theflowing of ink to be suppressed, and a small magnitude of resistanceagainst the flowing of ink arises around a discharge opening group 1f onthe left-hand end side of the ink jet head 21 due to the presence of thethird ink absorbing portion 26 having a lowest density, i.e., a coarsestructure without any hindrance against the flowing of ink, whereby thewhole flowing state of ink can be uniformalized further in addition tothe uniformalization of the flowing of ink attainable by the functionaleffect based on the structure of the ink jet apparatus in Embodiment 3.

In this embodiment, the ink absorbing member 26 constructed such thatthree ink absorbing portions each having a different density areintegrated with each other to constitute a single ink absorbing member.Alternatively, a plurality of separate ink absorbing portions eachhaving a different density may be arranged one after another on theupper surface 22b of the cap 22. This embodiment is advantageouslyapplicable especially when the ink jet head is designed in the form of amulti-discharge opening.

The ink jet head 21 and the cap 22 constructed in the above-describedmanner can practically be used like in Embodiment 4 by incorporatingthem in, e.g., the ink jet apparatus shown in FIG. 14.

[Embodiment 6]

FIG. 7 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with a sixth embodiment of the presentinvention, showing the structure of an ink jet head and capping meansconstituting the ink jet apparatus as essential components, and FIG. 8is a plan view of the capping means as viewed in the B arrow-markeddirection in FIG. 7, showing the state that a series of ink dischargeports formed on the ink jet head are arranged in the overlapped state.

A characterizing feature of this embodiment consists in that the ink jetapparatus has the substantially same structure as that of theconventional one shown in FIG. 12 and FIG. 13 and a flow restrictingmember 25 similar to that employed Embodiment 4 shown in FIG. 4 and FIG.5 is placed on a group of protuberances 2e formed on an upper surface 2aof a cap 2.

In this embodiment, the flow restricting member 25 causes a largemagnitude of resistance against the flowing of ink from a centraldischarge opening group 1e inclusive of the peripheral part of thelatter toward an ink suction port 2c to arise on the cap 2 with theresult that the flowing of ink can be suppressed with the aid of theflow restricting member 25. In addition, the flow restricting member 25causes a small magnitude of resistance against the flowing ink fromdischarge opening groups 1f and 1g located on the opposite end sides ofthe cap 2 toward an ink suction port 2c to arise on the cap 2 withoutany hindrance against the flowing of ink that way. Consequently, theflowing state of ink can positively be uniformalized with the ink jetapparatus.

The ink jet head 1 and the cap 2 can practically be used like inEmbodiment 1 by incorporating them in, e.g., the ink jet apparatus shownin FIG. 14.

[Embodiment 7]

FIG. 9 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with a seventh embodiment of the presentinvention, showing the structure of an ink jet head and capping meansconstituting the ink jet apparatus as essential components, and FIG. 10is a plan view of the capping means as viewed in the C arrow-markeddirection in FIG. 9.

A characterizing feature of this embodiment consists in that a flowrestricting member 27 exhibiting a special contour as shown in FIG. 10is substituted for the flow restricting member 25 constructed inaccordance with Embodiment 6.

In this embodiment, as shown in FIG. 10, the flow restricting member 27is prepared in the form of a substantially rectangular flat plate. Thegap between the flow restricting member 27 and a peripheral wall portion2b of the cap 2 is kept constant along the whole periphery of the flowrestricting member 27. A group of holes 27a each having a small diameterare formed through the central part of the flow restricting member 27, agroup of holes 27b each having a diameter larger than that each smallhole 27a are formed through the opposite end parts of the same, and agroup of holes 27c each having an intermediate diameter between those ofthe holes 27a and 27b are formed through the boundary area between boththe holes 27a and 27b. The holes 27a each having a smallest diameter areformed with a large distance between adjacent holes 27a, the holes 27beach having a largest diameter are formed with a small distance betweenadjacent holes 27b, and the holes 27c each having an intermediatediameter are formed with an intermediate distance between those of boththe holes 27a and 27c.

Since the flow restricting member 27 is constructed in theabove-described manner, a magnitude of resistance against the flowing ofink from a central discharge opening group 1e toward an ink suctionports 2c is increased, causing the flowing of ink in that way to besuppressed, and a magnitude of resistance against the flowing of inkfrom discharge opening groups 1f and 1g located on the opposite endsides of the flow restricting member 27 toward the ink suction port 2cis reduced without any hindrance against the flowing of ink.Consequently, the flowing state of ink can be uniformalized by the flowrestricting member 27.

The ink jet head 1 and the cap 2 constructed in that way can practicallyused like in Embodiment 1 by incorporating them in, e.g., the ink jetapparatus shown in FIG. 14.

[Embodiment 8]

FIG. 11 is a fragmentary sectional view of an ink jet apparatusconstructed in accordance with an eighth embodiment of the presentinvention, showing the structure of a recording head and capping meansconstituting the ink jet apparatus as essential components.

A characterizing feature of this embodiment consists in that the ink jetapparatus has the same structure as that of the conventional one shownin FIG. 12 and FIG. 13 and an ink absorbing member 28 including threekinds of ink absorbing portions each having a different density isplaced on a group of protuberances 2e formed on an upper surface 2a ofthe cap 2.

The ink absorbing portions of the ink absorbing member 28 constructed inaccordance with this embodiment are integrated with each other toconstitute a single integral structure. Specifically, the ink absorbingmember 28 is substantially composed of a first ink absorbing portion 28aarranged at the position facing to a central discharge opening group 1ewhile having a highest foaming density, i.e., a dense structure, secondink absorbing portions 28b arranged at the positions facing to dischargeopening groups 2f and 1g on the opposite end sides of the ink jet head 1with a lowest foaming density, i.e., a coarse structure, and third inkabsorbing portions 28c arranged between both the ink absorbing portions28a and 28b with an intermediate foaming density

In this embodiment, a magnitude of resistance against the flowing of inkfrom an ink feeding port it toward an ink suction port 2c is increased,causing the flowing of ink in that way to be suppressed, and magnitudeof resistance against the flowing of ink from the ink feeding port 1btoward the opposite ends of the cap 2 is reduced without any hindranceagainst the flowing of ink in this way. Consequently, the flowing stateof ink can be uniformalized by the ink absorbing member 28.

In this embodiment, three ink absorbing portions each having a differentdensity are molded integral with each other to constitute the inkabsorbing member 28. Alternatively, a plurality of separate inkabsorbing portions each having a different density may be arranged oneafter another for the same purpose as mentioned above.

The ink jet head 1 and the cap 2 constructed in the above-describedmanner are practically used like in Embodiment 1 by incorporating themin, e.g., the ink jet apparatus shown in FIG. 14.

In each of Embodiment 1 to Embodiment 8, an ink discharging elementconsisting of a plurality of discharge opening portions and a common inkchamber and an ink tank portion are integrally assembled with each otherto constitute an integral unit as an ink jet head. Alternatively, theink discharging element and the ink tank portion may separately beprepared in such a manner as to allow them to be detachably assembledwith each other.

The present invention can be also applied to a called full-line typerecording head whose length is not less than the maximum length across arecording medium.

As is apparent from the above description, according to the presentinvention, the ink jet apparatus is constructed such that an ink suctionport of the capping means is formed at a position where an image lineconnecting the ink suction port with the ink feeding port is crossedwith almost all of extending lines along the discharge direction of inkdischarged from the ink discharge openings, respectively, and moreover,flow restricting means is arranged in the capping means for reducing amagnitude of resistance against the flowing of ink around the inksuction port compared with a magnitude of resistance against the flowingof ink around the ink feeding port. Thus, a sufficiently acceptablesuction recovering state can be obtained over the whole range as seen inthe direction of a row of discharge openings by uniformalizing theflowing of ink flowing through the respective discharge openings whennegative pressure is applied to the ink jet head during suctionrecovering treatment, whereby an excellent quality of recorded image canbe maintained.

In the case that an ink absorbing member is arranged in the cappingmeans, a density of the ink absorbing member located around the inksuction port is reduced compared with a density of the same around theink feeding port. Also in the case that the ink feeding port is locatedopposite to the ink suction port, when flow restricting means isarranged in the capping means for properly adjusting a magnitude ofresistance against the flowing of ink around the ink feeding port, theflowing of ink through the respective discharge openings can beuniformalized when negative pressure is applied to the ink jet headduring suction recovering treatment, whereby a sufficiently acceptablesuction recovering state can be obtained over the whole range as seen inthe direction of a row of discharge openings, and moreover, an excellentquality of recorded image can be maintained.

In addition, according to the present invention, since there does notarise a necessity for setting an intensity of suction pressure or aquantity of sucked ink to a level higher than a required one in order torecoverably activate a discharge opening portion having poorflowability, pumping properties of the ink jet apparatus may be degradedwith the result that the ink jet apparatus can be designed andconstructed with smaller dimensions, and moreover, a quantity of ink tobe uselessly wasted can be reduced.

Further, since it is not required that the common ink chamber occupies alarge volume in order to reduce a magnitude of resistance against theflowing of ink from the ink feeding port of the ink jet head to therespective discharge openings, the ink jet head can be designed andconstructed with smaller dimensions, resulting in the whole ink jetapparatus being designed and constructed with smaller dimensions.Additionally, since a quantity of ink to be sucked during suctionrecovering treatment can be reduced, a quantity of ink to be uselesslywasted can also be reduced. It should be added that the advantageouseffects as mentioned above can remarkably be recognized when the ink jethead is designed in the form of a multi-discharge opening or it isdesigned with longer dimensions.

The present invention has been described in detail with respect to eightpreferred embodiments, and it should of course be understood thatchanges and modifications may be made without any departure away fromthe scope of the present invention in its broader aspects, and it is theintention, therefore, in the appended claims to cover all such changesand modifications as fall within the spirit of the present invention.

What is claimed is:
 1. An ink jet apparatus, comprising:capping meansfor capping a plurality of ink discharge openings of an ink jet headtherewith, the ink jet head including the plurality of ink dischargeopenings to downwardly discharge ink, a common ink chamber communicatedwith the plurality of ink discharge openings, and an ink feeding portfor feeding ink to the common ink chamber; sucking means for sucking inkfrom the plurality of ink discharge openings of the ink jet head throughan ink suction port while the ink jet head is capped by the cappingmeans, the ink suction port being arranged at a position apart from aposition opposing the ink feeding port; and an ink flow restrictingmeans for restricting a flow of the ink by said sucking means throughsaid plurality of discharge openings, a magnitude of restriction againstthe flow of ink from a given discharge opening being reduced incorrespondence to a distance from the given discharge opening to the inksuction port, the ink flow restricting means being arranged in thecapping means.
 2. An ink jet apparatus, comprising:capping means forcapping a plurality of ink discharge openings of an ink jet headtherewith, the ink jet head including the plurality of ink dischargeopenings to downwardly discharge ink, a common ink chamber communicatedwith the plurality of ink discharge openings, and an ink feeding portfor feeding ink to the common ink chamber; sucking means for sucking inkfrom the plurality of ink discharge openings of the ink jet head throughan ink suction port while the ink jet head is capped by the cappingmeans, the ink suction port being arranged at a position apart from aposition opposing the ink feeding port; and an ink absorbing member forabsorbing ink, the ink absorbing member being arranged in the cappingmeans, wherein a density of a given portion of the ink absorbing memberincreases in proportion to an increase in distance from the givenportion to the ink suction port.
 3. An ink jet apparatus as claimed inclaim 1 or 2, wherein the ink jet head includes an energy generatingelement for generating energy to be utilized for discharging ink fromthe plurality of ink discharge openings.
 4. An ink jet apparatus asclaimed in claim 3, wherein the energy generating element is anelectro-thermal converting element for generating thermal energy forallowing a phenomenon of film boiling to appear in ink.
 5. An ink jetapparatus as claimed in claim 1 or 2, wherein the plurality of inkdischarge openings are arranged in the row-shaped pattern across thewhole width of an ink receiving medium to which is ink discharged fromthe plurality of ink discharge openings.
 6. An ink jet apparatus,comprising:capping means for capping a plurality of ink dischargeopenings of an ink jet head therewith, the ink jet head including theplurality of ink discharge openings to downwardly discharge ink, acommon ink chamber communicated with the plurality of ink dischargeopenings, and an ink feeding port for feeding ink to the common inkchamber; sucking means for sucking ink from the plurality of inkdischarge openings of the ink jet head through an ink suction port whilethe ink jet head is capped by the capping means, the ink suction portbeing arranged at a position where a line connecting the ink suctionport with the ink feeding port crosses substantially all of a pluralityof lines extending along a discharge direction of ink discharged fromthe ink discharge openings; and an ink flow restricting means forrestricting a flow of ink by said sucking means through said pluralityof discharge openings, a magnitude of restriction against the flow ofink from a given discharge opening being reduced in correspondence to adistance from the given discharge opening to the ink suction port, theink flow restricting means being arranged in the capping means.
 7. Anink jet apparatus, comprising:capping means for capping a plurality ofink discharge openings of an ink jet head therewith, the ink jet headincluding the plurality of ink discharge openings to downwardlydischarge ink, a common ink chamber communicated with the plurality ofink discharge openings, and an ink feeding port for feeding ink to thecommon ink chamber; sucking means for sucking ink from the plurality ofink discharge openings of the ink jet head through an ink suction portwhile the ink jet head is capped by the capping means, the ink suctionport being arranged at a position where a line connecting the inksuction port with the ink feeding port crosses substantially all of aplurality of lines extending along a discharge direction of inkdischarged from the ink discharge openings; and an ink absorbing memberfor absorbing ink, the ink absorbing member being analyzed in thecapping means, wherein a density of a given portion of the ink absorbingmember increases in proportion to an increase in distance from the givenportion to the ink suction port.
 8. An ink jet apparatus as claimed inclaim 6 or 7, wherein the ink jet head includes an energy generatingelement for generating energy to be utilized for discharging ink fromthe plurality of ink discharge openings.
 9. An ink jet apparatus asclaimed in claim 8, wherein the energy generating element is anelectro-thermal converting element for generating thermal energy forallowing a phenomenon of film boiling to appear in ink.
 10. An ink jetapparatus as claimed in claim 9, wherein the plurality of ink dischargeopenings are arranged in the row-shaped pattern across the whole widthof an ink receiving medium to which ink is discharged from the pluralityof ink discharge openings.
 11. An ink jet apparatus, comprising:cappingmeans for capping a plurality of ink discharge openings of an ink jethead therewith, the ink jet head including the plurality of inkdischarge openings to downwardly discharge ink, a common ink chambercommunicated with the plurality of ink discharge openings, the chamberincluding an ink feeding port for feeding ink to the common ink chamber;sucking means for sucking ink from the plurality of ink dischargeopenings of the ink jet through an ink suction port while the ink jethead is capped by the capping means, the ink suction port being arrangedat a position apart from a position opposing to the ink feeding port;and a flow restricting means arranged in the capping means for reducinga magnitude of resistance against the flowing of ink corresponding tothe distance from the ink suction port.
 12. An ink jet apparatus asclaimed in claim 11, wherein the ink jet head includes an energygeneration element for generating energy to be utilized for dischargingink from the plurality of ink discharge openings.
 13. An ink jetapparatus as claimed in claim 12, wherein the energy generating elementis an electro-thermal converting element for generating thermal energyfor allowing a phenomenon of film boiling to appear in ink.
 14. An inkjet apparatus as claimed in claim 13, wherein the plurality of inkdischarge openings are arranged in the row-shaped pattern across thewhole width of an ink receiving medium to which ink is discharged fromthe plurality of ink discharge openings.
 15. An ink jet apparatus,comprising:capping means for capping a plurality of ink dischargeopenings of an ink jet head therewith, the ink jet head including theplurality of ink discharge openings to downwardly discharge ink, acommon ink chamber communicated with the plurality of ink dischargeopenings, the an ink feeding port for feeding ink to the common inkchamber; sucking means for sucking ink from the plurality of inkdischarge openings of the ink jet head through an ink suction port whilethe ink jet head is capped by the capping means, the ink suction portbeing arranged at a position apart from a position opposing to the inkfeeding port; and an ink absorbing member for absorbing ink, whose adegree of coarseness being increased in proportion to the distance fromthe ink suction port.
 16. An ink jet apparatus as claimed in claim 15,wherein the ink jet head includes an energy generating element forgenerating energy to be utilized for discharging ink from the pluralityof ink discharge openings.
 17. An ink jet apparatus as claimed in claim16, wherein the energy generating element is an electro-thermalconverting element for generating thermal energy for allowing aphenomenon of film boiling to appear in ink.
 18. An ink jet apparatus asclaimed in claim 17, wherein the plurality of ink discharge openings arearranged in the row-shaped pattern across the whole width of an inkreceiving medium to which ink is discharged from the plurality of inkdischarge openings.
 19. An ink jet apparatus, comprising:a cap forcapping a plurality of ink discharge openings for discharging ink froman ink jet head, said ink jet head including a common ink chambercommunicated with said plurality of ink discharge openings and an inkfeeding port for feeding ink to said common ink chamber; sucking meansfor sucking ink from said plurality of ink discharge openings while saidplurality of ink discharge openings are capped by said cap; and an inkflow restricting means arranged in said cap for restricting a flow ofink by said sucking means through said plurality of discharge openings,a magnitude of restriction against the flow of ink from a givendischarge opening being reduced in correspondence to a distance fromsaid given discharge opening to said ink feeding port.
 20. An ink jetapparatus as claimed in claim 19, wherein said ink flow restrictingmeans comprises an ink absorbing member for absorbing ink, wherein adensity of a given portion of said absorbing member is reduced incorrespondence to a distance from said given portion to said ink feedingport.
 21. An ink jet apparatus, comprising:a cap for capping a pluralityof ink discharge openings for discharging ink; sucking means for suckingink from said plurality of ink discharge openings through an ink suctionport in said cap while said plurality of ink discharge openings arecapped by said cap; and an ink flow restricting means arranged in saidcap for restricting a flow of ink by said sucking means through saidplurality of discharge openings, a magnitude of restriction against theflow of ink from a given discharge opening being reduced incorrespondence to a distance from said given discharge opening to saidink suction port.
 22. An ink jet apparatus as claimed in claim 21,wherein said ink flow restricting means comprises an ink absorbingmember for absorbing ink, wherein a density of a given portion of saidabsorbing member is reduced in correspondence to a distance from saidgiven portion to said ink suction port.
 23. A cap for capping aplurality of ink discharge openings for discharging ink, provided in anink jet apparatus comprising sucking means for sucking ink from saidplurality of ink discharge openings through an ink suction port in saidcap while said plurality of ink discharge openings are capped by saidcap, said cap comprising:an ink flow restricting means arranged in saidcap for restricting a flow of ink by said sucking means through saidplurality of discharge openings, a magnitude of restriction against theflow of ink from a given discharge opening being reduced incorrespondence to a distance from said given discharge opening to saidink suction port.
 24. A cap as claimed in claim 23, wherein said inkflow restricting means comprises an ink absorbing member for absorbingink, wherein a density of a given portion of said absorbing member isreduced in correspondence to a distance from said given to said inksuction port.